Process and apparatus for manufacturing sheets from polymerizable substantially solvent-free casting resins



y 8, 1962 K. H. GERBER 3,032,815

PROCESS AND APPARATUS FOR MANUFACTURING SHEETS FROM POLYMERIZABLESUBSTANTIALLY SOLVENT-FREE CASTING RESINS Filed Aug. 8, 1957 8Sheets-Sheet 1 INVIJNTOR.

HTTOR N E .l

y 1962 K. H. GERBER 3,032,815

PROCESS AND APPARATUS FOR MANUFACTURING SHEETS FROM POLYMERIZABLESUBSTANTIALLY SOLVENT-FREE CASTING RESINS Filed Aug. 8, 1957 8Sheets-Sheet 2 "n H "'l.

FIGQZ HTT'ORNEf/ May 8, 1962 K. H. GERBER 3,032,815

PROCESS AND APPARATUS FOR MANUFACTURING SHEETS FROM POLYMERIZABLESUBSTANTIALLY SOLVENT-FREE CASTING RESINS 8 Sheets-Sheet 3 Filed Aug. 8,1957 ,l lllv v l ll ll l l INVENTOR.

BY mt .lfiqw firm/way May 8, 1962 K. H GERBER 3,032,815

- PROCESS AND APPARATUS FOR MANUFACTURING SHEETS FROM POLYMERIZABLESUBSTANTIALLY SOLVENT-FREE CASTING RESINS 8 Sheets-Sheet 4 Filed Aug. 8,1957 INVENTOR.

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PROCESS AND APPARATUS FOR MANUFACTURING SHEETS FROM POLYMERIZABLESUBSTANTIALLY SOLVENT-FREE CASTING RESINS 8 Sheets-Sheet 5 Filed Aug. 8,1957 M- MW Mam INVENTOR.

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PROCESS AND APPARATUS FOR MANUFACTURING SHEETS FROM POLYMERIZABLESUBSTANTIALLY SOLVENT-FREE CASTING RESINS Filed Aug. 8, 1957 8Sheets-Sheet 6 XML BY Mal HTTORNEQ/ May 8, 1962 K. H. GERBER 3,032,815

PROCESS AND APPARATUS FOR MANUFACTURING SHEETS FROM POLYMERIZABLESUBSTANTIALLY SOLVENT-FREE CASTING RESINS 8 Sheets-Sheet 7 Filed Aug. 8,1957 |NV ENTOR ATTORNEY y 1962 K. H. GERBER 3,032,815

PROCESS AND APPARATUS FOR MANUFACTURIN EETS FROM POLYMERIZABLESUBSTANTIALL SOLVENT-FREE CASTING RESINS Filed Aug. 8, 1957 8Sheets-Sheet 8 HTTORNE 5/ United States Patent The present inventionrelates to a process and apparatus for manufacturing sheets frompolymerizable, substantially solvent-free, casting resins.

For some time now plastic sheets have been manufactured continuously inendless bands. For example, a solution of the plastic materialtogetherwith the addition of stabilizers and softeners in some cases is appliedto a rotating evaporation drum and within the period of time requiredfor almost one revolution the solvent is evaporated and the plastic ishardened to such a degree that it can be removed from the rotating drumand after sufficient ripening can be stored away. During the manufactureof such sheets no change takes place chemically in the plastic material.In particular there is no molecular expansion during the manufacture ofthe sheet so that the plastic material of the sheet has the samesolubility characteristics after the sheet is manufactured as thematerial had before it was made into a sheet.

Although sheets may be manufactured quickly and efiiciently in thismanner there are several undesirable limitations in this process ofmanufacture. Thus, the

requirement that the solvent evaporate to a very great extent during therelatively short time of less than one revolution of the drum limits theuse of the above process to extremely thin sheets since otherwise theextent of evaporation of the solvent is not sufiicient. Although sheetsobtained in this manner are qualitatively equal to many purposes andeven ideal for some purposes, the sheets obtained in this way are notsatisfactory where there is a requirement of resistance to dissolving,to softeners, to dyes, and to high temperature, and where there is arequirement of mechanical resistance to such actions as bending,pressure, cutting, frictional rubbing, etc.

Qualitatively the latter requirements are met by plastic plates whichare manufactured under heat and pressure in multi-layer presses with theuse of paper impregnated with urea or melamine resins.

In such presses the resins are chemically changed into plastics whichfor practical purposes cannot be dissolved or melted, i.e. thermosettingresins, and which have a high molecular weight. Also these materials areexceedingly strong mechanically. In manufacturing such plates it ispossible to continuously carry out the impregnation of the paper strips,but the pressing must be intermittently carried out.

One of the objects of the present invention is to provide plastic sheetshaving all of the above desirable properties (resisting dissolving andmelting, i.e. properties of thermosetting resins) but made continuouslyin a very quick and efiicient manner so that the disadvantages resultingfrom the non-continuous operation necessitated by the multi-layer pressare avoided.

Another object of the present invention is to manu-' facture suchplastic sheets together with other sheets to which the plastic sheetsare joined, these other sheets being sheets of wood, fleece, wovenfabric, etc.

A further object of the present invention is to use for the manufactureof sheets according to the present in-v vention devices which willguarantee proper application of the material to treating surfaces andthe like, such devices guaranteeing uniform thickness of a layer ofsheet material as well as eflicient distribution thereof, etc.

An additional object of the present invention is to provide a processand apparatus capable of manufacturing sheets of the above type indouble thicknesses, for example, and a process and apparatus capable offorming from a pair of such sheets elongated tubes which may be hollowor which may have any desired bodies located therein.

With the above objects in view the present invention mainly consists ofa process of manufacturing an article composed at least in part of asheet formed from a polyrnerizable, substantially solvent-free castingresin, this process including the steps of depositing a layer offlowable material composed of the casting resin and an additionalcomponent which reduces the hardening time thereof on a treating surfaceon which the deposited material hardens in a relatively short time, thencontinuously removing from the treating surface the layer of materialdeposited thereon, the material being continuously removed in the formof a continuous sheet, and the thus-obtained sheet is then furthertreated.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, to-

one possible process and apparatus according to the presout invention;

FIG. 2 is a diagrammatic illustration of another process and apparatusaccording to the present invention, the process illustrated in FIG. 2being carried out in a controlled atmosphere;

FIG. 3 illustrates a further process and apparatus according to thepresent invention;

FIG. 4 shows still another process and apparatus ac-- sheets of wood,for example;

FIG. 5 shows a process and apparatus capable of making a doublethickness of sheets according to the present invention;

FIG. 6 illustrates a particular apparatus used according to the presentinvention for manufacturing sheets and joining the same to other sheets;

FIG. 7 is a transverse sectional view taken along line 7-7 of FIG. 6 inthe direction of the arrows and show-' ing in particular the crosssection of a belt or endless band according to the present invention;

FIG. 8 is a partly diagrammatic, fragmentary, partly sectionalillustration of a particular combination of devices used formanufacturing a sheet according to the present invention;

FIG. 9 diagrammatically illustrates a process and apparatus which areused in accordance with the present invention to provide a sheet havinga desired pattern there- FIG. 10 diagrammatically illustrates a processand apparatus for manufacturing tubes from a pair of sheets according tothe present invention;

FIG. 11 illustrates in cross section a finished tube with an elongatedbody located therein;

FIG. 12 shows a tube which is hollow;

FIG. 13 is a fragmentary transverse view of one possible apparatusaccording to the present invention for v smoothing and eliminatingbubbles from a layer of material used to form a sheet according to thepresent invention; and

FIG. 14 is a sectional illustration fragmentarily showing anotherembodiment of a structure for smoothing and eliminating air bubbles frommaterials used to form a sheet according to the present invention.

For a few years now the so-called casting resins have been available,and such resins have the property of being able to be placed in adesired shape without the use of pressureas a more or less cohesiveliquid. Furthermore these resins either contain no solvents or if theydo contain a solvent the latter solvent such. as, for example, styrol,becomes converted under certain conditions with the dissolved materialinto hard polymerized bodies at temperatures which are so far below theboiling point of the solvent that practically no loss of solvent occursthrough evaporation, and moreover these resins have mechanical and otherproperties in such a wide range that they can be adapted to a largevariety of purposes, providing variations between elastic and hardmaterials, and by having combined with the resins such additions asdyes,.pigments, fillers, materials for providing protection againstlight, materials for increasing resistance to heat, developers,softeners, fibers, etc.

The so-called unsaturated polyester resins are an example of suchcasting resins, and these polyester resins are essentially composed ofeventually modified polyesters of tap-unsaturated dicarboxylic acidsmixed with liquid substances in the reactive group CH =C These andsimilar casting resins can be used in the manufacture of sheets by beingplaced upon highly polished flat surfaces and then before or after thematerial hardens it can be joined with a carrier sheet such as a sheetof plywood or the like using a layer of adhesive, or after hardening thesheet is simply withdrawn from the negative plate so as to be availablefor further treatment.

The present invention takes advantage of the fact that it is possible toinfluence to a very large extent the hardening time of such castingresins by the addition thereto of suitable catalysts and by mixingtogether suitable types while heating the same through a relatively lowminimum temperature. In accordance with the present invention the timerequired for hardening of the casting resins is so greatly reduced bythe use of such additions with the resins that the resins can be used ina continuous process for making sheets such as that which heretofore hasbeen suitable only for the manufacture of extremely thin sheets. After asheet is formed according to the present invention it is further treatedas by being joined with other objects such as other sheets, also inaccordance with the present invention.

For the process of the present invention all casting resins may be usedwhich are fiowable, which harden at an infinitely slow rate at roomtemperature, which harden very quickly at high temperatures, and whichdo not lose any considerable amount of volatile components duringpolymerization. The following partially polymerized materials areexamples of materials having the required properties, these materialsbeing used in a condition where they are not fully polymerized:unsaturated polyesters, ethoxylene casting resins, and phenol castingresins such as phenol formaldehyde. As catalysts which will reduce thehardening time of the casting resins the following materials aresuitable: organic peroxides such as benzoyl peroxide, cumenehydroperoxide, cyclohexanone peroxide, lauryl peroxide,methylethylketone peroxide; also organic amines such asethylene-diamine, ethylene-triamine, and dipropylene-triamine;furthermore certain inorganic acids such as hydrochloric acid,phosphoric acid, and sulfuric acid; and organic acids such as forexample p-toluene sulfonic acid as well as acid salts such as ammoniumchloride and ammonium nitrate.

Referring now to FIG. 1 there is illustrated therein a hollow rotatabledrum 1 whose outer surface forms a treating surface used for treatingmaterial according to the present invention, this drum being rotatedabout its axis 2. The drum is driven so that its speed of rotation canbe continuously regulated. An unillustrated heating means is located inthe interior of the drum. A means 3 is provided for directing a streamof material 3a against the outer treating surface of the drum 1, andthis means 3 is in the illustrated example a suitable spray nozzle whilethe material 3a is in the form of a powder or liquid which preventssticking of the casting resin against the outer treating surface of therotating drum 1. A means 4 is provided for directing a stream offlowable casting resin together with a material for reducing thehardening time thereof onto the treating surface 1 and the materialcomposed of the casting resin and the catalyst for reducing thehardening time thereof is indicated at 12 both in the form of the streamwhich is provided by the means 4 illustrated as taking the form of anozzle as Well as the layer of material 12 deposited on the treatingsurface of the drum 1.

In order to prevent the material 12' from sticking to the treatingsurface any of the following materials may be sprayed by the nozzle 3onto the surface of the drum: paraffin dissolved in benzene or paraffinhydrocarbons, or silicone oils dissolved in benzene hydrocarbons; also,gelatin dissolved in water, or bone glue dissolved in water, andpolyvinyl alcohol dissolved in water or ethyl alcohol.

Suitable rollers 1.4a and pressure rollers 14 are provided so as toguide a bendable plate 15 to the main drum 1 so that the plate 15 passesthe main drum 1 and in so doing becomes joined with the sheet 12' beforethe outer surface thereof is hardened. The drum 1 rotates in thedirection of arrow 11 and the nozzles 3 and 4 are supported in such away that they can be adjustably shifted through a predetermined angle soas to have their positions with respect to the axis of rotation of thedrum I adjusted so that the angular distance 041 and the angulardistance (x can be regulated, the latter distance being the angulardistance between the last pressure roller 14 and the nozzle 3 while theformer angular distance a is the distance between the nozzles 3 and 4angularly about the axis of rotation of the drum 1. By adjusting thepositions of these nozzles it is possible to adjust the ratio betweenthe available working time with respect to the material emanating fromnozzle 4, i.e., the time during which the material remains in workable,not completely hardened, condition, and the time for spraying materialsfrom the nozzles 3 and 4. The absolute amount of working time iscontrolled by the speed of rotation of the drum 1. The fiowable materialcomposed of the casting resin and the additional component which reducesthe hardening time thereof is deposited by the nozzle 4 on the rotatingouter surface of the drum 1 continuously, and as the drum 1 turns in thedirection of arrow 11 of FIG. 1 the flowable material deposited on thetreating surface hardens and is completely hardened by the time itbecomes located at the angular position of the rightmost pressure roll14 of FIG. 1. The outer surface of the layer of material 12 is stillsoft enough so that this layer be comes joined with the sheet 15 ofplywood or the like, for example, as the latter moves along the rolls14a and 14 in the manner illustrated in FIG. 1. It will be noted thatthe hardened sheet 12 is continuously moved from the treating surface ofthe drum 1 while being continuously joined and advanced together withthe additional sheet 15..

In FIG. 2 the elements indicated with reference characters 1, 2, 6, 3a,4, 11 and 12 are the same as those described above and illustrated withthe same characters in FIG. 1. Also, the angles a and a correspond tothose of FIG. 1. However, it will be noted that in the em bodiment ofFIG. 2 there are no series of guiding and pressure rolls 14a and 14 andinstead there is a single roll 13 which is placed in the position of thelast pressure roll 14 of FIG. 1 and which serves to remove the hardenedsheet .12 continuously from the rotating treating surface of thedrum'li. The angle at indicated in FIG, 2 thus represents the angleavailable for polymerization and together with the speed of rotationcontrols the degree of polymerization that will be obtained. Thepolymerizing drum 1 as well as the removing roll 13 and the nozzles 3and 4 are housed within a container 1a which is closed off from theouter atmosphere except for the opening at the bottom wall of thecontainer through which the sheet 12 moves, as indicated in FIG. 2. Inthe particular example shown in FIG. 2 the material is sprayed throughthe nozzles 3 and 4 with the use of gases under pressure which are inertto the reaction taking place so that they do not produce any undesirableinfluence on the operation. These gases under pressure which are usedfor providing the streams or sprays of material 3a and 12 fill thecontainer 1a and maintain in the latter a pressure greater thanatmospheric pressure and these gases escape through the bottom wallopening through which the sheet 12 moves so that this opening for thesheet 12 as well as openings for the bearings of the shaft 2 of the drum1 and the like need not be provided with any particular sealingstructures. After the sheet 12 moves out of the container 1a it travelspast a nozzle 18 which directs to one of the faces of the sheet 12 alayer of a suitable adhesive, and then the sheet 12 arrives at thepressure or squeezing rollers 16 indicated in FIG. 2. A suitableconveyor belt indicated diagrammatically by the arrow 21) in FIG. 2serves to move a series of flat plates 17 such as plywood plates, forexample, to the right, as viewed in FIG. 2, and these plates 17 becomejoined with the sheet 12 due to the layer of adhesive on the latter aswell as the pressure applied between the rollers 16 and the conveyorbelt carrying the plates 17, and in this way additional sheets arejoined to the sheet 12 as the latter leaves the treating surface. In theevent that a binary adhesive is used then the upper faces of the sheetsor plates 17, as viewed in FIG. 2, may be provided with a layer of thesecond component of the adhesive, this layer being applied by the nozzle19 indicated in FIG. 2.

In FIG. 3 also those elements indicated with the reference characters 1,2, 3, 3a, 4, 11 and 12 indicate the same elements which are indicatedwith these reference characters in FIGS. 1 and 2, and also the angles aand a are the same as those of FIG. 2. In FIG. 3 a removing roll 13 isprovided rather than a series of rolls 14 as in FIG. 1. The angle 01;;indicated in FIG. 3 represents the time or angle available beforeapplying to the outer surface of the partially polymerized layer 12 aweb of Woven fabric 6 derived from a roll of this fabric 5. Withsuitable relatively simple supports it is possible to adjust the angles:1 a and on; so that they have any desired sizes. The pressure roll 7serves to apply to the outer face of the web 6 another layer of aplastic material of the same properties as the layer 12', and this otherlayer is supplied to the roll 7 by the rolls 8 and 9 in the mannerindicated diagrammatically in FIG. 3. Thus, the web 6 becomes locatedbetween the pair of plastic sheets 10 and 12 which are joined to eachother and which are fully hardened when they leave the treating surface1 at the roll 13.

In the embodiment of the invention which is illustrated in FIG. 4 thetreating surface instead of taking the form of the outer cylindricalsurface of a rotating drum takes the form of the outer surface of anendless band. Thus, it is the outer surface of the endless band 23 whichformsthe treating surface with the embodiment of FIG. 4. This band 23 iscarried and moved by the pulleys or rolls 21 and 22 which are driven atthe same rates of speed and in the directions indicated by the arrows inFIG. 4. The endless band 23 need not be made of a single piece ofmaterial and instead can be made up of a plurality of individual panelswhich are linked together and which can be used when it is desired tomake individual plates rather than a long continuous sheet. Of course,such plates are simply small sheets. Of course, where suchinterconnected panels are used the rolls 21 and 22 will not have acylindrical configuration and instead will have a polygon-a1 crosssectional configuration corresponding to the individual panels which arenot bendable.

In the embodiment illustrated in FIG. 4 there is located over the leftend of the band 23, as viewed in FIG. 4 a container 24 which forms partof the means for directing to the treating surface the layer of flowablematerial in accordance with the present invention. The container 24 hasthe material supplied to it through a conduit 25 and the materialdischarges through the opening 27, the rate of discharge beingcontrolled by the threaded screw 26 whose bottom end extends partly intothe opening 27, and a device 30 is provided for guaranteeing that'thethickness of the layer is uniform and also for removing air bubbles. Theelements 24-27 and 30 are extremely schematic illus trations in FIG. 4of structure which is described in greater detail below. With thisstructure the layer of material 28 is applied to the treating surfaceformed by the outer face of the endless band 23. A plurality of rolls 29serve to support the upper run of the band 23 in the embodiment of FIG.4 while an elongated plate 31 is located next to the lower run of thebelt 23 to prevent this lower run from deviating from the desiredstraight path. If desired the plate 31 may be located next to theunderside of the upper run in order to support the latter in the sameway as the rolls 29. The rolls 29 form spaces between themselves throughwhich heat rays derived from suitable heating elements 35 may move tothe band 23 so as to heat the material on its outer surface.

The layer 28 of the material deposited upon the treating surface movesin the direction of the anrow of FIG. 4 and as soon as it reaches theright end of the band 23 the layer of material 28 moves around with theband to the underside of the bottom run thereof and when the sheet 28 isfully hardened or at least in a partially hardened condition it contactsanother sheet or plate 32 which becomes in this way joined with theendless layer 28 which thus becomes a continuously applied coating onone of the faces of the plate or sheet 32. A suitable adhesive may beused on the plate 32 for promoting the binding thereof with the coating28, and if desired the adhesive may be applied to the outer face of theband 28. The means for applying such layers of glue or the like to thesheets is not illustrated in FIG. 4. The plate or plates 32 which are tobe covered with a coating of the material 28 are moved along by thetransport rolls 33 and by the pressure rolls 34 which press the plates32 toward the bottom run of the band 23, and it is apparent that thepressure rolls 34 cooperate with the plates 31 to press the sheet 28 andthe plates or sheet 32 into engagement with each other so as to providea proper joint therebetween. Instead of pressure rolls 34 it is alsopossible to use a second endless band which accomplishes the same resultas the pressure rolls 34 but which is carried and driven only by a pairof rolls. The heating devices 35 which are arranged beneath the upperrun of the band 23 may be in the form of infra red lamps, for example.These devices are illustrated in the drawings simply as by havingupwardly directed parabolic reflecting surfaces.

FIG. 5 shows an apparatus capable of manufacturing in accordance withthe process of the present invention a double thickness of the materialor a double sheet with an insert embedded therein. In the embodiment ofFIG. 5 a pair of endless band arrangements similar to that shown in FIG.4 are provided. An endless band 43 is carried and driven by a pair ofrolls 41 and 4 2 and forms the upper band and the elements 44-47 and 50indicate the structure for applying to the outer treating surface of theband 43 a layer of the flowable material used in accordance with thepresent invention. The layer 48 of the material which is in this wayapplied to the outer surface of the band 43 moves in the direction ofthe upper arrow of FIG. 5 together with the endless band 43 whose upperrun is supported by the rolls 49 and this layer 48 is of course moved bythe smoothing device 50, the material 48 being derived'from theelongated opening or slot 47 of the container 44. The lower run' of theband 43 is supported by an elongated plate 51 and of course instead ofthis plate 51 rolls may be provided. Furthermore, such rolls or plates49 and 51 may be replaced by endless bands each of which is carried anddriven by :a pair of rolls. Below the upper run of the endless band 43are arranged the heating devices 55 which may be in the form of infrared lamps.

A lateral guide roll 56 shown at the left of FIG. serves to guide to theouter surface of the substantially hardened sheet 48 as it moves alongthe lower run of the band 43 another sheet 57 in the form of a wovenfabric or in the form of fleece, or the sheet 57 may be in the form of aband of any desired material or may even take the form of sepanateplates used to reinforce the double sheet manufactured with thearrangement illustrated in FIG. 5. The lower sheet of the doublethickness is provided by a structure similar to that which provides theupper sheet 48. The lower assembly includes the endless band 63- whichis carried and driven by the pair of rolls 61 and 62, and the materialdepositing means 64-67 and '70, which is described in greater detailbelow in connection with FIG. 8, serves to apply the material to theouter treating surface of the band 63.

This band 63 is supported at its lower run by the rolls 69 and theelement 70 serves to smooth the material delivered from the chamber 64through the elongated slit 67 as well as to guarantee a uniformdistribution of the material 68 on the treating surface of the band 63.A plate 71 is used to support the upper run of the band 63, and justabove the lower run of this band are located the infra red heating lamps75, for example. Thus, with the structure shown in FIG. 5 a pair ofsheets are simultaneously formed and as they move to the right, asviewed in FIG. 5, in engagement with each other so as to be united toeach other they have placed therebetween the third band or sheet 57which serves to reinforce the final construction.

FIGS. 6 and 7 illustrate an endless band according to the presentinvention which serves as a pressure means and which may be used, forexample, instead of the rolls 34 of FIG. 4.

In FIG. 6 the pressure means formed by the endless band is shown asbeing used to press downwardly upon the sheet of plastic which hasalready been formed and which is in engagement with the other sheet orplate to which it is to be joined. Of course, the arrangement may bereversed so that the sheet 164 and plate 165 of FIG. 6 are located inengagement with the upper run of the band 163 shown in FIG. 6 so thatthis band then presses upwardly against the sheet 164 so as to move thelatter into engagement with the plate 165 and press the elements 164 and165 together with a force which will provide, a proper jointtherebetween. Only one end of the band is shown in FIG. 6 since theother end is the same and the upper and lower runs are simplycontinuations of the structure shown in FIG. 6.

A polygonal roll 80 carries a chain band 81 in the form of a pluralityof individual grates which are linked together so as to form an endlessband, and the runs of thi band are supported by the rolls 82, asindicated diagrammatically in FIG. 6. An elongated hollow endless pusherband 163 is carried by the chain band 81, and this band 163 serves topress the sheet 164 downwardly against the plate 165 moving to the rightwith the sheet 164, as viewed in FIG. 6. The hollow interior of the band163 is filled with an elastic medium so that the longitudinal centralportion of the outer wall of the band 163 bulges outwardly to thedot-dash line 166 indicated in FIG. 6. Therefore, as the endless bandrotates it will engage the sheet 164 for the first time at the point 167which is located by the distance a in front of the point 169 where fullpressure is applied. As a result a pressure is applied by pressureapplying means in the shape of an isosceles triangle whose base extendstransversely across the sheet 164 at the point 169 and whose apex isrounded and located at the point 167. Thus, the pressure band 163provides first a wedge-like action so that air bubbles located betweenthe sheet 164 and the plate 165 will be squeezed outwardly toward theouter side edges of the sheet.

FIG. 7 shows the structure of FIG. 6 in transverse cross section at anenlarged scale, and the supporting roll 82 is shown in FIG. 7 supportingthe grate 81, FIG. 7 also showing the band 163 in engagement with thechain grate 81. As may be seen from FIG. 7 the hollow interior 170 ofthe band 163 has the cross section of an isosceles triangle with theapex of the triangle directed toward the sheet 164 and the base of thetriangle located I at the part of the belt which is engaged by the chaingrate 81. Therefore, at the outer wall of the band 163 this band is of alesser thickness along its longitudinal central line than at its sideedges. The interior 170 is filled with a metal alloy of low meltingpoint. Any metal alloy having a melting point somewhat below C. may beused. In particular Woods alloy may be used, this alloy being composedof 25% lead, 50% bismuth, l2 /2% cadmium, and l2 /z% tin, and this alloyhaving a melting point of approximately 60 C., or Roses metal may beused, this latter alloy being composed of approximately 50% bismuth, 25%tin, and 25% lead and having a melting point of approximately 95 C. Inorder to heat the alloy located within the hollow space 170 of the belt,metal electrodes 171 are carried by the belt at its side walls andextend into the hollow interior thereof, these electrodes having outerfree ends which slide along the bus bars 172 which serve to provide inthe electrodes 171 the necessary heating current for melting the alloywithin the hollow band 163.

FIG. 8 shows in a partly diagrammatic manner the details of anembodiment of the invention used for applying the material to thetreating surface. A mixing container 101 is provided and a stirrerextends into this container. The stirrer 102 serves to mix thoroughlywith the casting resin the additional component which reduce thehardening time thereof so that this latter catalyst becomes thoroughlymixed with the casting resin. The outlet 103 serves to direct thematerial from the container 101 into a vacuum chamber 104 communicatingwith a conduit 105 which leads to a vacuum pump which serves to maintainthe desired vacuum within the vacuum chamber 104 which is notillustrated in the drawings. Thus, the degassed mass leaves the vacuumchamber 104 and is moved by a metering pump 106 along the conduit 107into the entrance pipe 108 of the depositing means. The conduit 103serves to provide a thin stream of the material from the container 101into the vacuum chamber 104 so that a thorough degassing takes place.

The pipe 108 serves to deliver the material to a receiving chamber 109and from the receiving chamber 109 the material moves to a dischargingchamber 112. A means is provided between the chambers 109 and 112 forproviding communication therebetween and for guaranteeing uniform flowof the material from the receiving chamber 109 to the delivering chamber112, and this means takes the form of a partition wall formed betweenand common to the chambers 109 and 112 and formed along its length witha plurality of openings 110 one of which is shown in FIG. 8. Each of theopenings 110'is of a frustoconical configuration and has its smaller enddirected toward the discharge chamber 112. The top wall of the chamber109 carries a plurality of screw members 111 having bottom conical endswhich respectively extend into the openings 110 and which have the sameinclination of the surfaces of the openings so that by adjusting thepositions of the bottom ends of the screws 111 with respect to theopenings 110, it is possible to regulate the flow of the material fromthe chamber 109 to the chamber 112, and thus a uniform flow along theentire length of the device may be provided.

The bottom wall of the chamber 112 is in the form of a plate 113 fixedto a rearwardly directed flange of the rear wall of the chamber 112 byscrews 114 having heads 115 which engage the underside of the plate 113and which are of a larger diameter than the width of slots 116 throughwhich the screws 114 respectively extend. With the screws 114 which arecarried by nuts at their top ends, as viewed in FIG. 8, it is possibleby cooperation of the slots 116 with the shanks of the screws to adjustthe position of the plate 113 so that the distance between its rightedge and the right wall of the chamber 112, as viewed in FIG. 8, may beregulated so that the width of the discharge gap of the dischargechamber 112 may in this way be adjusted. The plate 113 is provided withan unillustrated hollow space which contains a cooling medium. The masswhich reaches the cylindrical polymerizing surface 117 through the gapforms on the surface 117 the sheet 118. At the end of the materialdepositing device there is provided at one of the end faces of thepolymerizing roll 117 a lateral sealing plate 119 which in anunillustrated manner is hollow and cooled with water and which serves todetermine the width of the sheet. Of course, a similar sealing plate 119is located at the opposite end of the apparatus, which is to say at theopposite end of the roller 117.

In order to accurately adjust the thickness of the sheet 118 a lineardistributor element 128 is located over the polymerizing surface 117.The distributor element 120 is formed out of a length of sheet metalwhich is rolled around at one end thereof and which has its rolled endwelded at 121 to the remainder of the sheet metal so as to provide theelongated hollow chamber 122 to which cooling water is supplied by theconduit 123. Of course, another conduit 123 may be provided so thatcooling water may be continuously circulated through the hollow chamber122 of the distributor 120. In order to be able to adjust thedistributor 129 to different distances from the polymerizing surface117, the vertical wall of the distributor 120 is formed with a pluralityof slots 124 which extend vertically and through which extend screwmembers 125 which serve to clamp the distributor 1220 to the front wallof the chambers 109 and 112. Thus, by loosening the screws 125 theheight of the distributor 120 may be adjusted and then the screws 125may be tightened so as to clamp the distributor 120 in its adjustedelevation.

FIG. 9 of the drawings illustrates a polymerizing drum 130 having anouter cylindrical polymerizing surface for manufacturing a sheetaccording to the present invention. The sheet 131 is formed on thepolymerizing surface in the manner described above, this sheet 131 beingapplied in the form of material 132 from a material depositing meanshaving the above-described construction. A pattern drum 133 is locatednext to the polymerizing drum 139 and is provided with projections 134extending radi ally outwardly from the axis of the pattern drum 133 inaccordance With a predetermined pattern. A supply roll 135 receives alayer of material 137 from the supply container 136 and guides thislayer in the form of a cohesive coating 138 to the pattern drum 133where the outer ends of the projections 134 engage the layer 138 toremove the latter from the roll 135 and to deposit the material in thepattern determined by the shape of the projections 134 onto thepolymerizing surface of the polymerizing roll 130, portions 140 of thematerial deposited on the surface of the drum 130 being shown in FIG. 9.It is after these pattern portions are deposited on the drum that thelatter receives the material 131 which is formed into the sheet 132. Thematerial 137 which is used to form the pattern 140 is the same materialwhich is used for the sheet 132 and thus becomes polymerized in the sameway. However, the material 137 may have a different color, for example.Thus, when the finished sheet is removed from the polymerizing drum 130it has embedded in its upper surface portion, as viewed in FIG. 9,

10' the pattern 141 whose particular design is controlled by the patterndrum 133.

FIG. 10 of the drawings shows a process according to the presentinvention for manufacturing tubes. A pair of sheets 240 manufacturedaccording to the present invention move simultaneously to the right, asviewed in FIG. 10. Such a pair of sheets may be simultaneouslymanufactured by a structure as shown in FIG. 5 where the upper and lowerassemblies are spaced from each other so that the two sheets issuingfrom the right of the structure of FIG. 5 have between them the spaceindicated between the sheets 240 at the left of FIG. 10. Between thesesheets which are moving together toward the right are located insuccession a plurality of elongated rods of cylindrical cross section,and these rods may be inserted between the sheets by hand, for example.Also, suitable devices such as the nozzles referred to above may beprovided for spraying a coating of adhesive on the faces of the sheetswhich are directed toward each other. FIG. 10 shows a rod 241a which hasjust been inserted between the sheets 240. The rod 241b was insertedjust before the rod 241a. Between these two rods a pair of pressingmembers 242 come together so as to press the two sheets together as theycontinue to move toward the right, as viewed in FIG. 10, and due to theadhesive put between these sheets, as indicated in FIG. 10, they stickto each other. Of course, the sheets may be in such condition that theirsurfaces which are to be joined to each other are not yet fully hardenedand they may stick to each other in a sufficiently satisfactory mannersimply by their still somewhat plastic condition. The pressure members242 which come together in the manner indicated in FIG. 10 may each forma part of a toothed wheel which turns about an axis perpendicular to thedirection of movement of the sheets 240 in such a way that the members242 participate in the movement of the sheets and at the same time movetoward and away from the sheets so that the two members 242 reach theposition indicated in FIG. 10 at the proper moment. After the sheetshave been joined in this way a pair of additional pressure members 243push the sheets together between a pair of successive rods, as is shownin FIG. 10 between the rods 24-112 and 2410, the latter rod having beeninserted before the rod 24117. Any suitable mechanism is moved formoving the pressure members 243 toward and away from each other in theproper synchronism. Preferably the speed of rotation of the toothedwheel having the teeth 242 is such that the latter teeth or pressuremembers 242 engage the sheets at a rate somewhat faster than the rate ofthe cycles of operation of the pressure members 243 so that the sheetstend to become upset just before they are put together by the members243. The pressing of the sheets together by the members 243 provides atube which closely surrounds the rod, as is indicated at the right ofFIG. 10 where the rod 241d is shown surrounded by the pair of sheetswhich are joined together. At this time a pair of blades 245 cometogether under the actuation of a suitable mechanism so as to cut therod 241d and its covering from the oncoming series of rods covered withsheets. The pair of flanges of the sheets extending to the right andleft from the rod 241d, as viewed in FIG. 10, are removed in anysuitable way so as to provide the structure shown in FIG. 11, namely arod 241e sheathed within a tubular closure 2492. If it is desired tohave a hollow tube then the rods are provided with a suitable coatingwhich will prevent them from sticking to the sheet material, and after astructure as shown in FIG. 11 is provided the rod may then be removedfrom the interior of the tube so that a hollow elongated tube as shownin FIG. 12 is provided in this way. The structure shown in FIG. 10 ismoved to the right of FIG. 10 in any suitable conveyor which in thiscase is not in the form of a continuous band but is rather in the formof a series of chain elements or panels which are spaced from each otherso that in the spaces between the panels of the conveyor the elements242, 243

and 245 may work, these elements being moved in synchronism with theconveyor so that they move into and out of the spaces between thesections of the conveyor without engaging the sections.

FIG. 13 shows the drive for a smoothing device such as that indicated inFIG. 4 by the reference character 30 and in FIG. 5 by the referencecharacter 50. The smoothing device consists essentially of an elongatedlinear body located relatively close to the polymerizing surface andmoves to the right and left transversely with respect to the surface.The polymerizing surface of a rotating drum, for example, is indicatedat 250 in FIG. 13, and over this surface is shown the movable smoothingelement 251. The structure for depositing the plastic material onto thepolymerizing surface 250 is not shown. The smoothing element 251 isfixed to an elongated bar 252 having ends respectively extending intothe bearing blocks 253 and 254, these bearings supporting the bar 252and the smoothing element 251 for longitudinal shifting movement in thedirection of their lengths, which is to say in a direction substantiallyparallel to the axis of rotation of the polymerizing drum 250. Thebearings are such that they have non-circular openings of square crosssection, for example, which receives portions of the bar 252 which alsoare of square or mating cross section so that while the bar 252 togetherwith the smoothing elements 251 can shift back and forth they cannotturn about the axis of the bar 252.

The bar 252 is fixedly connected to a pair of guide members 255 whichreceive into the space defined be tween themselves a portion of a collar256 which is fixed to a shaft 257 supported at its right end, as viewedin FIG. 13, by the bearing 254 for rotation about its axis. Also, thebearing 254 supports the shaft 257 for longitudinal shifting movement.The left end of the shaft 257, as viewed in FIG. 13 terminates in anelongated hollow tubular portion 258 open at its left extremity, asviewed in FIG. 13, and receiving a drive shaft 259 which is supported bythe bearing 253 and which is driven by pulley 260 fixed to the left endof the drive shaft 259. The hollow tubular portion 258 of the shaft 257is formed with an elongated axially extending slot 262, and the driveshaft 259 carries a cross pin 261 which extends into the slot 262 sothat in this way the shaft 257 is constrained to rotate together withthe drive shaft 259 but at the same time is axially shiftable withrespect thereto. The hollow tubular end portion 258 of the shaft 257fixedly carries as by having formed integrally therewith an annular cam263 which is shaped as indicated in FIG. 13 so that it has a peripherysimilar to that of a helix. The bearing 253 fixedly carries a block 265formed with a notch 264 which receives the periphery of the cam 263.Thus, as the shaft 257 is driven by the shaft 259 the periphery of thecam 263 by cooperating with the notch 264 causes the shaft 257 to beshifted longitudinally back and forth, and by cooperation of the collar256 with the guides 255 the bar 252 as well as the smoothing element 251will also be shifted longitudinally back and forth.

With the embodiment of FIG. 13 the elongated smoothing element 251 movesin a direction parallel to the polymerizing surface. In the embodimentshown in FIG. 14 the smoothing element moves radially with respect tothe axis of rotation of the polymerizing surface so as to move towardand away from the polymerizing surface. The polymerizing surface 278 isshown in FIG. 14 fragmentarily and in cross section so that it appearsas an arc of a circle. The layer of material 271 which forms a sheetaccording to the invention is shown on the polymerizing surface 278 incross-section, and the structure for depositing the flow of material onthe polymerizing surface is omitted from FIG. 14. A hollow tubularsmoothing and pressing element 272 is located over the polymerizingsurface 278 with the material 271 extending between the surface 278 andthe element 272, and the interior hollow space 273 of the elongatedtubular element- 272'may be cooled as by having cooling water circulatedtherethrough. The elongated hollow tubular member 272 has fixed theretoa bar 274 which extends upwardly through a suitable bearing 275 whichguides the bar 274 for vertical reciprocating movement, the bar 274 aswell as the opening of the bearing 275 being noncircular so that the bar274 cannot turn about its axis and is constrained only to verticalreciprocating movement.

The bar 274 terminates at its top end in a head portion 276 which isbifurcated and which receives between its bifurcations an elongatedlever 279, each of the bifurcations of the bar 276 being formed with anelongated slot 277 and the lever 279 carrying a cross pin 270 whichrespectively extends into the slots 277. Only one of the bifurcationsand slots 277 is visible in FIG. 14. The lever 279 is supported by apivot pin 280 for pivotal turning movement about a stationary axis, andthe right end of the lever 279 is bifurcated and receives between itsbifurcations 281 an eccentric 282 which is fixed to a shaft 283 forrotation therewith, this shaft 283 being driven by a motor 285 which iscarried by the support 284 which also supports shaft 283 for rotationabout its axis. Thus, with the structure of FIG. 14 while the motor 185drives the shaft 283 the eccentric 282 will rotate with theshaft andwill cooperate with the bifurcated portion 281 of the shaft 279 to turnthe shaft 279 up and down through a relatively small angle about thepivot axis formed by the shaft 280, and as a result the bar 274 willshift slightly up and down so as to move the elongated tubular member272 also up and down through a slight distance. This slight up and downmovement of the bar 272 will also cause the layer of material depositedon the polymerizing surface to become uniformly distributed thereover.

In the above description reference has been made to webs of fabric,fleece, or the like, which are located between or against the sheetsconstructed according to the present invention so as to become joinedtherewith. These webs may be made of a woven fabric of natural orsynthetic fibers as well as a fabric woven from metal wires such aswires made of copper or bronze and also glass and asbestos fibers may beused in some cases. It is also possible to use fleece made of natural orsynthetic glass and asbestos fibers. Also, in many cases it is desirableto use absorbent layers such as sheets of cardboard or paper with thesheets of the present invention.

As a specific example of operations according to the present invention,referring to FIG. 8, the container 101 may hold approximately kg. of thecasting resin and catalyst according to the present invention. Forexample this 75 kg. may be composed of an unsaturated polyester togetherwith a catalyst such as benzoyl peroxide, the latter being added in suchan amount as to hasten the hardening time of the unsaturated polyesterthat it will harden within the period of time available on the rotatingpolymerizing surface. Both of these components are mixed thoroughly inthe container 101 by the stirrer 10-2 and while the mixing is takingplace the conduit 103 is closed, the mixing being continued beyond theabsolute minimum required. The vacuum pump connected to the conduit 165places the interior of the chamber 104 at a pressure of mm. of mercury.After the material has been mixed to the desired extent in the container181 the conduit 193 is opened and the outlet of-this conduit is in theform of an elongated narrow slit so that a thin stream of the materialis sucked into the container 1&4 and the air bubbles drawn into themixture during the mixing thereof burst within the vacuum chamber 164.This degassing of the material is necessary since otherwise the trapped.air bubbles would provide a porous construction of the sheet. Thecontainer 101 and the vacuum chamher 194 are dimensioned in such a waythat it is at the most necessary to provide an additional batch ofmaterial once an hour.

The pump 106 which may be in the form of a screw pump supplies the rawmaterial at a uniform rate into the receiving chamber 109 irrespectiveof whether the conduit 193 is opened or closed. The material is thendelivered from the chamber 109 to the polymerizing surface in the mannerdescribed above in the detailed description of FIG. 8. The drive for thepolymerizing roll 117 is adjustable so that the latter may be driven ata speed which is suitable for the particular material which is beingworked with. Moreover, a drive is transmitted from the polymerizing roll117 to the pump 106 so that the latter is always driven at a rate whichis proportional to the speed of drive of the polymerizing roll 1.17. Inthis way it is assured that the raw material supplied to the roll willalways have the same thickness irrespective of whether the polymerizingdrum is driven at a relatively slow or fast rate. Moreover, the speed ofdrive of the drum controls the thickness of the layer thereon. Byadjusting this drive it is possible to obtain a variation from 1 to 3,which is to say the thickness of the sheet may be regulated to anywherebetween 300 and 900 microns. Within the interior of the drum 117 islocated a bath which is controlled by .a suitable thermostat so as to beheated to the desired temperature. Before the raw material reaches thepolymerizing surface a suitable pattern may be placed thereon as wasdescribed above.

The action of the smoothing devices such as the device 30 of FIG. 4 iscontrolled so that this device swings up and down at such a speed thatthe desired results are produced. For example, depending upon the speedof rotation of the polymerizing drum, the temperature of the materialand the components thereof the smoothing device is operated in such away as to provide the desired smooth surface. When the sheetis removedby a roll such as the roll 13 of FIG. 3 and when it has not yet reachedits 100% final condition as to degree of polymerization and hardnessupon further cooling there are no noticeable changes such as shrinking,embrittlement, and the like. A pre determined amount of ripening may bedesired, and in this case the sheet is guided through an unillustratedripening chamber where it is placed for a period of 200- 300 seconds inan atmosphere having a temperature of IOU-120 C. In general the heatingmay take place with the use of infra red lamps, but also it is possibleto use vapors such as steam for this purpose.

During the continued movement of the sheet it is provided on one facewith a layer of adhesive so as to be capable of being joined withanother sheet or plate, as described above. A particularly suitableadhesive is a polyurethane glue made by the Bayer Company. This gluerequires as a solvent esters of low boiling point which provide a strongswelling of the sheet after a relatively long period'of time while thesheet is still freshly It is necessary therefore that the evaporationof,

made. the solvent, after the principal portion thereof has evaporatedwithout any particular assisting means during a period of approximately120 seconds, be completed in a period of approximately 60 seconds whilethe infra red heating is maintained. The effect produced by thissubsequent heating cannot be replaced by a longer evaporating time andnot by any additional circulation of air under pressure.

With an arrangement as shown in FIG. 2 the sheet 12 must cool down to atemperature of approximately 50 C. before it is joined with one of theplates 17, and this cooling takes place simply during the free movementof the sheet to the rolls in in a period of approximately l53() secondsdue to the natural cooling of the material. Where the plates 17 arerelatively thick so that they hold heat longer it may be necessary toprovide an additional cooling medium such as providing cooling streamsof air.

in the above-described structure the endless bands which have thepolymerizing surfaces may be moved .at a rate of approximately 3 cm. persecond. The sheet which is mately 30 seconds to cool off, approximatelyseconds to evaporate and approximately 60 seconds for such evaporationwhen the temperature is elevated, again 30 seconds for cooling andfinally 60 seconds for pressing. Thus, the total treating time for thesheet after it leaves the polymerizing surface is approximately 300seconds.

Where sheets of reinforcing fabric or the like are inserted between apair of sheets of the invention which are joined together in the mannerdescribed above in connection with FIG. 5, for example, these insertedwebs may be impregnated with the same resin as that of which the sheetsare composed. Where it is possible to use an inexpensive resin whichwill fade in the light such as a phenol resin which is not non-fading,then this resin may be used to impregnate the inserted reinforcing webwhile the outer layers are then made of a more expensive but non-fadingpolyester resin.

Although in the above-described process and apparatus reference has beenmade to the spraying onto the polymerizing surface of a suitable agentwhich willprevent sticking of the plastic to the surface, it is alsopossible to mix together with the plastic material an agent which willprevent sticking thereof on the polymerizing surface, and in this caseof course it is unnecessary to deposit onto the polymerizing surface acoating to prevent sticking.

The rhythmically moving smoothing devices such as those shown in FIGS.13 and 14 and described above cause gas bubbles to be freed from thelayer of material which has not yet fully hardened.

In connection with FIG. 2 reference has been made above to inert gasesfilling the chamber 101, these gases being derived from the inert gaseswhich are under pressure and used in connection with the nozzles 3 and 4for spraying the material 3a and 12 onto the polymerizing drum 1.However, it is also possible to fill the interior of the chamber 1a withany gas from any suitable source, this gas having no undesirableinfluence on the process, and

it is not absolutely essential to employ for the nozzles 3' and 4 a gasunder pressure which will fill the chamber 1a. Instead of a chamber 1ait is also possible to use any suitable tank or the operations may takeplace under a suitable hood.

,Where additional sheets, plates, or the like are to be joined to thesheets made according to the present invention, these sheets may bepreheated so as to form a good bond with the plastic sheets, and also itis possible to provide on the surfaces which are to contact and tobecome bound together a catalyst which will promote the union of thesheet with the additional sheets, plates, or the like. Of course, rapidcooling and quenching of the plastic sheet may be provided as it leavesthe polymerizing surface.

In those cases where the sheet is not yet in a fully hardened conditionas it leaves the polymerizing surface, it may be desirable to providefor ripening of the sheet over a predetermined length of time, and forthis purpose the sheet maybe divided into sections or folded into layerswhich form overlying sections and the sections of the sheet may beprevented from sticking to each other by suitable intermediate layerssuch as sheets of paper inserted between the sections of the sheet orcoatings of powder, and then the sheet may be stored at any desiredlocation for ripening purposes. located in a container which isinsulated at all sides against the transfer of heat.

While the sheet is still in a somewhat plastic condition aroll having aprofile of predetermined pattern marked thereon may be pressed againstthe sheet so as to press a desired pattern into the sheet.

The sheets of the invention can also be corrugated so as to have a shapesimilar to that of one of the sheets of FIG. 10, for example, by passingthe sheets while they are still not in fully polymerized conditionthrough suitably shaped rolls which corrugate the sheets, the sheetsbeing thereafter heated. The corrugated sheets which are formed in thisway may be cut in any desired way so as to- For this purpose the sheetmay be provide individual channels, for example, or so as to providedesired lengths of corrugated rigid plastic. Of course,

these sheets may be joined together in the manner described above inconnection with FIG. 10.

In connection with FIG. 10, it is possible to use instead of the barsdescribed above a foam which is used as a core within the tube, such afoamy material serving as an insulation against heat and noise.Forexample the inserts maybe in the form of foam rubber.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofprocess and apparatus for making sheet material differing from the typesdescribed above.

While the invention has been illustrated and described as embodied inprocess and apparatus for making plastic sheet material having desiredproperties, it is not intended to be limited to the details shown, sincevarious modifications and structural changes may be made withoutdeparting in any way from the spirit of the present invention.

Without further analysis, the foregoing will also fully reveal the gistof the present invention that others can by applying current Knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed asnew and desired to be secured by Letters Patent is:

1. In a continuuous process for manufacturing an article composed atleast in part of a sheet formed from a polymerizable, thermosettingcasting resin selected from the group consisting of unsaturatedpolyesters, phenol and ethoxylene casting resins, the steps ofcontinuously applying to a revolving support a layer of predeterminedthickness of a fiowable mixture of a casting resin and of an agentadapted to reduce the hardening time of said casting resin at apredetermined elevated temperature to a predetermined relatively shortperiod of time, said mixture being adapted to harden at saidpredetermined elevated temperature without giving off any appreciableamount of gaseous products, so as to form a layer of said mixture onsaid revolving support; placing on said support before it is engaged bysaid fiowable mixture a material separate from said fiowable mixture ina predetermined pattern so that the pattern of said separate materialbecomes embedded in the surface of the fiowable mixture which engagesthe revolving support; heating said mixture on said support to saidpredetermined elevated temperature; adjusting the speed of saidrevolving support relative to said predetermined period of time in sucha manner that said mixture will be substantially hardened prior tocompletion of one revolution of said revolving support; and continuouslyseparating the thusformed hardened sheet of casting resin from saidsupport, whereby in a single application and in a continuous manner asheet of said predetermined thickness is formed of said polymerizable,thermosetting casting resin.

2. In a continuous process for manufacturing an article composed atleast in part of a sheet formed from a polymerizable, thermosettingcasting resin selected from the group consisting of unsaturatedpolyester, phenol and ethoxylene casting resins, the steps ofcontinuously applying to a revolving support a, layer of predeterminedthickness of allowable mixture of a casting resin and of an agentadapted to reduce the hardening time of said casting resin at apredetermined elevated temperature to a predetermined relatively shortperiod of time, said mixture being adapted to harden at saidpredetermined elevated temperature without giving off any appreciableamount of gaseous products, so as to form a layer of said mixture onsaid revolving support; heating said mixture on saidsupport to saidpredetermined elevated temperaiii ture; adjusting the speed of saidrevolving support relative to said predetermined period of time in sucha manner that said mixture will be substantially hardened prior to.completion of one revolution of said revolving support; and continuouslyseparating the thus-formed hardened sheet of casting resin from saidsupport, whereby in a single application and in a continuous manner asheet of said predetermined thickness is formed of said polymerizable,thermosetting casting resin.

3. In a process as defined in claim 2, the step of vibrating saidmixture on said revolving support so as to smoothen and to remove gasbubbles from said layer during hardening of the same.

4. In a continuous process for manufacturing an article composed atleast in part of a sheet formed from a polymerizable, thermosettingcasting resin selected from the group consisting of unsaturatedpolyesters, phenol and ethoxylene casting resins, the steps ofcontinuously applying to a revolving support a layer of predeterminedthickness of a fiowable mixture of a casting resin and of an agentadapted to reduce the hardening time of said casting resin at apredetermined elevated temperature to a predetermined relatively shortperiod of time, said mixture being adapted to harden at saidpredetermined elevated temperature without giving off any appreciableamount of gaseous products, so as to form a layer of said mixture onsaid revolving support; applying to said flowable mixture before itengages said revolving support an additional material which preventssaid fiowable mixture from Sticking to said support; heating saidmixture on said support to said predetermined elevated temperature,adjusting the speed of said revolving support relative to saidpredetermined period of time in such a manner that said mixture will besubstantially hardened prior to completion of one revolution of saidrevolving support; and continuously separating the thus-formed hardenedsheet of casting resin from said support, whereby in a singleapplication and in a continuous manner a sheet of said predeterminedthickness is formed of said polymerizable, thermosetting casting resin.

5. In a continuous process for manufacturing an article composed atleast in part of a sheet formed from a polymerizable, thermosettingcasting resin selected from the group consisting of unsaturatedpolyesters, phenol and 'ethoxylene casting resins, the steps ofcontinuously applying to the outer face of a revolving drum a layer ofpredetermined thickness of a fiowable mixture of a casting resin and ofan agent adapted to reduce the hardening time of said casting resin at apredetermined elevated temperature to a predetermined relatively shortperiod of time, said mixture being adapted to harden-at saidpredetermined elevated temperature without giving off any appreciableamount of gaseous products, so as' to form a layer of said mixture onsaid revolving drum; heating said mixture on said drum to saidpredetermined elevated temperature; adjusting the speed of saidrevolving drum relative to said predetermined period of time in such amanner that said mixture will be substantially hardened prior tocompletion of one revolution of said revolving drum; and continuouslyseparating the thusformed hardened sheet of casting resin from saiddrum, whereby in a single application and in a continuous manner a sheetof said predetermined thickness is formed of said polymerizable,thermosetting casting resin.

6. In an apparatus for manufacturing an article composed at least inpart of a sheet formed from a polymerizable thermosetting casting resinin plastic condition, in combination, a receiving chamber for receivingthe resin in fiowable form together with a component which reduces thehardening time thereof; a discharge chamber formed with an elongatedstraight slot-shaped discharge opening for discharging the material infiowable sheet form onto a treating surface; means associated with andprovidingcomrnunication between said receiving and discharge chamber andmaintaining uniform the rate of flow of the material from said receivingchamber to said discharge chamber so that the material flows throughsaid elongated straight slot-shaped discharge opening at a substantiallyuniform rate in the form of a flowable sheet of substantially uniformthickness, said flowable sheet of uniform thickness being deposited ontosaid treating surface; elongated hollow shaping means located adjacentto and extending in direction of said elongated straight slotshapeddischarge opening and simultaneously adjacent to and spaced from saidtreating surface a distance equal to the desired thickness of thefinished sheet material so as to serve as shaping means for saidflowable sheet material; and means for admitting cooling medium intosaid hollow shaping means for cooling said shaping means during shaping.

7. In an apparatus for manufacturing an article composed at least inpart of a sheet formed from a polymerizable thermosetting casting resinin plastic condition, in combination, a receiving chamber for receivingthe resin in flowable form together with a component which reduces thehardening time thereof; a discharge chamber formed with an elongatedstraight-shaped discharge opening for discharging the material inflowable sheet form onto a treating surface; means associated with andproviding communication between said receiving and discharge chamber andmaintaining uniform the rate of How of the material from said receivingchamber to said discharge chamber so that the material flows throughsaid elongated straight slot-shaped discharge opening at a substantiallyuniform rate in the form of a flowable sheet of substantially uniformthickness, said flowable sheet of uniform thickness being deposited ontosaid treating surface; elongated hollow shaping means located adjacentto and extending in directions of said elongated straight slot-shapeddischarge opening and simultaneously adjacent to and spaced from saidtreating surface a distance equal to the desired thickness of thefinished sheet material so as to serve as shaping means for saidflowable sheet material; means for admitting cooling medium into saidhollow shaping means for cooling said shaping means during shaping; andmeans for mounting said elongated hollow shaping means adjustably in adirection towards and away from said treating surface so as to adjustthereby the thickness of the finished sheet material.

References Cited in the file of this patent UNITED STATES PATENTS2,072,105 Fischer Mar. 2, 1937 2,144,548 Safford Jan. 17, 1939 2,198,621Izard Apr. 30, 1940 2,361,374 Abbott Oct. 31, 1944 2,438,089 Carson Mar.16, 1948 2,448,585 Fuller Sept. 7, 1948 2,495,640 Muskat Jan. 24, 19502,503,518 Slaughter Apr. 11, 1950 2,537,126 Francis Jan. 9, 19512,558,773 Mulloy et a1. July 3, 1951 2,559,649 Little et a1. July 10,1951 2,579,138 Burness Dec. 18, 1951 2,590,186 Land Mar. 25, 19522,643,700 Havens June 30, 1953 2,665,450 Lindquist Jan. 12, 19542,771,388 Rocky Nov. 20, 1956 2,799,609 Dalton July 16, 1957 FOREIGNPATENTS 546,469 Great Britain July 15, 1942

7. IN AN APPARATUS FOR MANUFACTURING AN ARTICLE COMPOSED AT LEAST INPART OF A SHEET FORMED FROM A POLYMERIZABLE THERMOSETTING CASTING RESININ PLASTIC CONDITION, IN COMBINATION, A RECEIVING CHAMBER FOR RECEIVEINGTHE RESIN IN FLOWABLE FORM TOGETHER WITH A COMPONENT WHICH REDUCES THEHARDENING TIME THEREOF; A DISCHARGE CHAMBER FORMED WITH AN ELONGATEDSTRAIGHT-SHAPED DISCHARGE OPENING FOR DISCHARGING THE MATERIAL INFLOWABLE SHEET FORM ONTO A TREATING SURFACE; MEANS ASSOCIATED WITH ANDPROVIDING COMMUNICATIN BETWEEN SAID RECEIVEING AND DISCHARGE CHAMBER ANDMAINTAINING UNIFORM THE RATE OF FLOW OF THE MATERIAL FROM SAID RECEIVINGCHAMBER TO SAID DISCHARGE CHAMBER SO THAT THE MATERIAL FLOWS THROUGHSAID ELONGATED STRAIGHT SLOT-SHAPED DISCHARGE OPENING AT A SUBSTANTIALLYUNIFORM RATE IN THE FORM OF A FLOWABLE SHEET OF SUBSTANTIALLY UNIFORMTHICKNESS, SAID FLOWABLE SHEET OF UNIFORM THICKNESS BEING DEPOSITED ONTOSAID TREATING SURFACE; ELONGATED HOLLOW SHAPING MEANS LOCATED ADJACENTTO AND EXTENDING IN DIRECTIONS OF SAID ELONGATED STRAIGHT SLOT-SHAPEDDISCHARGE OPENING AND SIMULTANEOUSLY ADJACENT TO AND SPACED FROM SAIDTREATING SURFACE A DISTANCE EQUAL TO THE DESIRED THICKNESS OF THEFINISHED SHEET MATERIAL SO AS TO SERVE AS SHAPING MEANS FOR SAIDFLOWABLE SHEET MATERIAL; MEANS FOR ADMITTING COOLING MEDIUM INTO SAIDHOLLOW SHAPING MEANS FOR COOLING SAID SHAPING MEANS DURING SHAPING; ANDMEANS FOR MOUNTING SAID ELONGATED HOLLOW SHAPING MEANS ADJUSTABLY IN ADIRECTION TOWARDS AND AWAY FROM SAID TREATING SURFACE SO AS TO ADJUSTTHEREBY THE THICKNESS OF THE FINISHED SHEET MATERIAL.